If the earth had no oceans, then the tropical regions would be comparatively warmer.
The earth without the ocean would be super-hot at the equator and really cold at the poles. The warming at the equator increases the temperature and the warm air rises. Without oceans, there will not be any winds flowing which will cause moderation of temperature, due to which extreme temperatures will be experienced in places such as extreme cold in the frigid zone and extreme heat in the equatorial region. Though temperature at tropics would be comparatively lower than equatorial region, still it would be high for the person to live in such areas hospitably. Ocean currents act similar to a conveyor belt, which transports warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics.
